Ukraine’s telecommunications system has come under attack, with equipment installed in Russian-controlled Crimea used to interfere with the mobile phones of members of parliament, the head of Ukraine’s SBU security service said on Tuesday.

“I confirm that an IP-telephonic attack is under way on mobile phones of members of Ukrainian parliament for the second day in row,” Valentyn Nalivaichenko told a news briefing.

“At the entrance to (telecoms firm) Ukrtelecom in Crimea, illegally and in violation of all commercial contracts, was installed equipment that blocks my phone as well as the phones of other deputies, regardless of their political affiliation,” he said.

“The security services are now seeking to restore at least the security of communications,” he said. “All state information security systems were unprepared for such a brazen violation of the law.”